Abstract: Landscape connectivity is an essential indicator for ecological processes and functions of habitat landscape, which plays an important role in the research of ecological processes such as biological migration and dispersal, interference diffusion, and gene flow. In this study, we used the Quickbird image of Yuanyang County, Yunnan Province in 2010 to study river and ditch corridors in Quanfuzhuang watershed of Yuanyang County. By means of graph theory, two calculating units (node and corridor) were selected to calculate landscape connectivity and importance index with five distance thresholds of 500, 1000, 2000, 4000 and 6000 m. With the graph of Hani terraced landscape corridor structure, the importance index of connectivity and corridor were analyzed, with further analysis and planning of landscape pattern. The results showed that the degree of connectivity indicated the importance of corridors to a greater extent, and reflected their connection situations. Meanwhile, connectivity degree increased with the increase of threshold value. Besides, the analysis of importance index showed that the importance index was higher for the corridors connected with different blocks in intensive river network, while the importance index of the longer corridors was higher in sparse river network. The study provides ideas for the ecological conservation and planning of Hani Rice Terraces, and also new insights for landscape connectivity research.

Key words: soil physical and chemical property, freeze-thaw, wind erosion, water erosion.